arrow-fx-coroutines / arrow.fx.coroutines.stream / fold1

fold1

fun <O> Pull<O, Unit>.fold1(f: (O, O) -> O): Pull<Nothing, O?>

Folds all inputs using the supplied binary operator, and writes the final result to the output of the supplied Pull when the stream has no more values.

fun <O> Stream<O>.fold1(f: (O, O) -> O): Stream<O>

Folds all inputs using the supplied operator f, and emits a single-element stream, or the empty stream if the input is empty, or the never stream if the input is non-terminating.

import arrow.fx.coroutines.stream.*

//sampleStart
suspend fun main(): Unit =
  Stream(1, 2, 3, 4, 5)
    .fold1 { a, b -> a + b }
    .toList()
    .let(::println) // [15]
//sampleEnd